Top 10 Reasons For Fermentation Failure

By Ed Kraus

Reason #2Adding Too Much Sugar At The Beginning Of Fermentation:

When a fermentation occurs what is really happening is the wine yeast is consuming sugar and turning it into alcohol. So the amount of sugar that is available to the wine yeast controls how much alcohol that can be made. But contrary to reason, it is possible to have too much sugar in a fermentation.

If the sugar concentration level of the must becomes too high at any given point--either at the beginning or during the fermentation--it starts to have an inhibiting effect on the yeast's ability to produce alcohol. In other words, the higher sugar concentration starts to act as a preservative effecting the fermentation in a negative way.

Before you add sugar to a batch, it is necessary to know how much sugar is already being provided by the fruit. This can vary dramatically from one fruit to the next. For example, in the case of most California grown grapes, no sugar is required at all to produce a wine with a reasonable level of alcohol--say 10 to 13 percent--but when making berry wines a considerable amount of sugar is required to obtain those same levels.

If you have a good wine recipe from a reliable source, such as wine making books, you can normally depend on the amount of sugar the recipe is calling for. Or certainly if you are following directions that were provided with wine making kits, your sugar level should be no issue whatsoever, just follow the directions.

But if you have a recipe from a questionable source or you are going it alone, it is strongly recommended that you control your sugar levels with the aid of a wine hydrometer, or find a reliable, trusted recipe from EC Kraus Here.

A wine hydrometer can tell you how much sugar is already in the must as well has how much sugar to add to end up with a potential alcohol level that is desirable.

It does this with a scale that is called "Potential Alcohol." The more sugar that is in the must, the higher the percentage reading will be on the Potential Alcohol scale.

At the beginning of fermentation having "Potential Alcohol" readings higher than 13% will usually interfere with the yeast's ability to start fermenting. Realize that most all wines you buy commercially are between 10% and 13%, so this is really no big issue.

But there are some of you out there--and you know who you are--that seek to drive the alcohol as high as possible. This is okay, but it is necessary to feed some of the sugar throughout the fermentation instead of adding all of it to the must up front.

By feeding sugar in this way you will be able to achieve higher alcohol without getting your sugar concentration levels too high. You are giving some of the original sugars time to turn into alcohol. This in turn will make room for the additional sugars you are feeding.

If you do not feed sugar in this way when attempting to achieve higher alcohol levels, you will be setting yourself up for potential fermentation problems.

-----------------------------------------------------------------------------------------------------------------------------Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.